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author | Linus Torvalds <torvalds@linux-foundation.org> | 2017-04-09 18:05:25 +0200 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-04-09 18:05:25 +0200 |
commit | 462e9a355e7488fde3712c3b2585fc2f2a2c263d (patch) | |
tree | 2f1cdf7e4b72281f9fba51b6d1515c2b46f8434b /arch | |
parent | Merge tag 'driver-core-4.11-rc6' of git://git.kernel.org/pub/scm/linux/kernel... (diff) | |
parent | Merge branch 'kprobe-fixes' of https://git.linaro.org/people/tixy/kernel into... (diff) | |
download | linux-462e9a355e7488fde3712c3b2585fc2f2a2c263d.tar.xz linux-462e9a355e7488fde3712c3b2585fc2f2a2c263d.zip |
Merge branch 'fixes' of git://git.armlinux.org.uk/~rmk/linux-arm
Pull ARM fixes from Russell King:
"A number of ARM fixes:
- prevent oopses caused by dma_get_sgtable() and declared DMA
coherent memory
- fix boot failure on nommu caused by ID_PFR1 access
- a number of kprobes fixes from Jon Medhurst and Masami Hiramatsu"
* 'fixes' of git://git.armlinux.org.uk/~rmk/linux-arm:
ARM: 8665/1: nommu: access ID_PFR1 only if CPUID scheme
ARM: dma-mapping: disallow dma_get_sgtable() for non-kernel managed memory
arm: kprobes: Align stack to 8-bytes in test code
arm: kprobes: Fix the return address of multiple kretprobes
arm: kprobes: Skip single-stepping in recursing path if possible
arm: kprobes: Allow to handle reentered kprobe on single-stepping
Diffstat (limited to 'arch')
-rw-r--r-- | arch/arm/mm/dma-mapping.c | 20 | ||||
-rw-r--r-- | arch/arm/mm/nommu.c | 5 | ||||
-rw-r--r-- | arch/arm/probes/kprobes/core.c | 49 | ||||
-rw-r--r-- | arch/arm/probes/kprobes/test-core.c | 11 |
4 files changed, 69 insertions, 16 deletions
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c index 63eabb06f9f1..475811f5383a 100644 --- a/arch/arm/mm/dma-mapping.c +++ b/arch/arm/mm/dma-mapping.c @@ -935,13 +935,31 @@ static void arm_coherent_dma_free(struct device *dev, size_t size, void *cpu_add __arm_dma_free(dev, size, cpu_addr, handle, attrs, true); } +/* + * The whole dma_get_sgtable() idea is fundamentally unsafe - it seems + * that the intention is to allow exporting memory allocated via the + * coherent DMA APIs through the dma_buf API, which only accepts a + * scattertable. This presents a couple of problems: + * 1. Not all memory allocated via the coherent DMA APIs is backed by + * a struct page + * 2. Passing coherent DMA memory into the streaming APIs is not allowed + * as we will try to flush the memory through a different alias to that + * actually being used (and the flushes are redundant.) + */ int arm_dma_get_sgtable(struct device *dev, struct sg_table *sgt, void *cpu_addr, dma_addr_t handle, size_t size, unsigned long attrs) { - struct page *page = pfn_to_page(dma_to_pfn(dev, handle)); + unsigned long pfn = dma_to_pfn(dev, handle); + struct page *page; int ret; + /* If the PFN is not valid, we do not have a struct page */ + if (!pfn_valid(pfn)) + return -ENXIO; + + page = pfn_to_page(pfn); + ret = sg_alloc_table(sgt, 1, GFP_KERNEL); if (unlikely(ret)) return ret; diff --git a/arch/arm/mm/nommu.c b/arch/arm/mm/nommu.c index 3b5c7aaf9c76..33a45bd96860 100644 --- a/arch/arm/mm/nommu.c +++ b/arch/arm/mm/nommu.c @@ -303,7 +303,10 @@ static inline void set_vbar(unsigned long val) */ static inline bool security_extensions_enabled(void) { - return !!cpuid_feature_extract(CPUID_EXT_PFR1, 4); + /* Check CPUID Identification Scheme before ID_PFR1 read */ + if ((read_cpuid_id() & 0x000f0000) == 0x000f0000) + return !!cpuid_feature_extract(CPUID_EXT_PFR1, 4); + return 0; } static unsigned long __init setup_vectors_base(void) diff --git a/arch/arm/probes/kprobes/core.c b/arch/arm/probes/kprobes/core.c index b6dc9d838a9a..ad1f4e6a9e33 100644 --- a/arch/arm/probes/kprobes/core.c +++ b/arch/arm/probes/kprobes/core.c @@ -266,11 +266,20 @@ void __kprobes kprobe_handler(struct pt_regs *regs) #endif if (p) { - if (cur) { + if (!p->ainsn.insn_check_cc(regs->ARM_cpsr)) { + /* + * Probe hit but conditional execution check failed, + * so just skip the instruction and continue as if + * nothing had happened. + * In this case, we can skip recursing check too. + */ + singlestep_skip(p, regs); + } else if (cur) { /* Kprobe is pending, so we're recursing. */ switch (kcb->kprobe_status) { case KPROBE_HIT_ACTIVE: case KPROBE_HIT_SSDONE: + case KPROBE_HIT_SS: /* A pre- or post-handler probe got us here. */ kprobes_inc_nmissed_count(p); save_previous_kprobe(kcb); @@ -279,11 +288,16 @@ void __kprobes kprobe_handler(struct pt_regs *regs) singlestep(p, regs, kcb); restore_previous_kprobe(kcb); break; + case KPROBE_REENTER: + /* A nested probe was hit in FIQ, it is a BUG */ + pr_warn("Unrecoverable kprobe detected at %p.\n", + p->addr); + /* fall through */ default: /* impossible cases */ BUG(); } - } else if (p->ainsn.insn_check_cc(regs->ARM_cpsr)) { + } else { /* Probe hit and conditional execution check ok. */ set_current_kprobe(p); kcb->kprobe_status = KPROBE_HIT_ACTIVE; @@ -304,13 +318,6 @@ void __kprobes kprobe_handler(struct pt_regs *regs) } reset_current_kprobe(); } - } else { - /* - * Probe hit but conditional execution check failed, - * so just skip the instruction and continue as if - * nothing had happened. - */ - singlestep_skip(p, regs); } } else if (cur) { /* We probably hit a jprobe. Call its break handler. */ @@ -434,6 +441,7 @@ static __used __kprobes void *trampoline_handler(struct pt_regs *regs) struct hlist_node *tmp; unsigned long flags, orig_ret_address = 0; unsigned long trampoline_address = (unsigned long)&kretprobe_trampoline; + kprobe_opcode_t *correct_ret_addr = NULL; INIT_HLIST_HEAD(&empty_rp); kretprobe_hash_lock(current, &head, &flags); @@ -456,14 +464,34 @@ static __used __kprobes void *trampoline_handler(struct pt_regs *regs) /* another task is sharing our hash bucket */ continue; + orig_ret_address = (unsigned long)ri->ret_addr; + + if (orig_ret_address != trampoline_address) + /* + * This is the real return address. Any other + * instances associated with this task are for + * other calls deeper on the call stack + */ + break; + } + + kretprobe_assert(ri, orig_ret_address, trampoline_address); + + correct_ret_addr = ri->ret_addr; + hlist_for_each_entry_safe(ri, tmp, head, hlist) { + if (ri->task != current) + /* another task is sharing our hash bucket */ + continue; + + orig_ret_address = (unsigned long)ri->ret_addr; if (ri->rp && ri->rp->handler) { __this_cpu_write(current_kprobe, &ri->rp->kp); get_kprobe_ctlblk()->kprobe_status = KPROBE_HIT_ACTIVE; + ri->ret_addr = correct_ret_addr; ri->rp->handler(ri, regs); __this_cpu_write(current_kprobe, NULL); } - orig_ret_address = (unsigned long)ri->ret_addr; recycle_rp_inst(ri, &empty_rp); if (orig_ret_address != trampoline_address) @@ -475,7 +503,6 @@ static __used __kprobes void *trampoline_handler(struct pt_regs *regs) break; } - kretprobe_assert(ri, orig_ret_address, trampoline_address); kretprobe_hash_unlock(current, &flags); hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) { diff --git a/arch/arm/probes/kprobes/test-core.c b/arch/arm/probes/kprobes/test-core.c index c893726aa52d..1c98a87786ca 100644 --- a/arch/arm/probes/kprobes/test-core.c +++ b/arch/arm/probes/kprobes/test-core.c @@ -977,7 +977,10 @@ static void coverage_end(void) void __naked __kprobes_test_case_start(void) { __asm__ __volatile__ ( - "stmdb sp!, {r4-r11} \n\t" + "mov r2, sp \n\t" + "bic r3, r2, #7 \n\t" + "mov sp, r3 \n\t" + "stmdb sp!, {r2-r11} \n\t" "sub sp, sp, #"__stringify(TEST_MEMORY_SIZE)"\n\t" "bic r0, lr, #1 @ r0 = inline data \n\t" "mov r1, sp \n\t" @@ -997,7 +1000,8 @@ void __naked __kprobes_test_case_end_32(void) "movne pc, r0 \n\t" "mov r0, r4 \n\t" "add sp, sp, #"__stringify(TEST_MEMORY_SIZE)"\n\t" - "ldmia sp!, {r4-r11} \n\t" + "ldmia sp!, {r2-r11} \n\t" + "mov sp, r2 \n\t" "mov pc, r0 \n\t" ); } @@ -1013,7 +1017,8 @@ void __naked __kprobes_test_case_end_16(void) "bxne r0 \n\t" "mov r0, r4 \n\t" "add sp, sp, #"__stringify(TEST_MEMORY_SIZE)"\n\t" - "ldmia sp!, {r4-r11} \n\t" + "ldmia sp!, {r2-r11} \n\t" + "mov sp, r2 \n\t" "bx r0 \n\t" ); } |